multifd-zstd.c (8436B)
1 /* 2 * Multifd zlib compression implementation 3 * 4 * Copyright (c) 2020 Red Hat Inc 5 * 6 * Authors: 7 * Juan Quintela <quintela@redhat.com> 8 * 9 * This work is licensed under the terms of the GNU GPL, version 2 or later. 10 * See the COPYING file in the top-level directory. 11 */ 12 13 #include "qemu/osdep.h" 14 #include <zstd.h> 15 #include "qemu/rcu.h" 16 #include "exec/ramblock.h" 17 #include "exec/target_page.h" 18 #include "qapi/error.h" 19 #include "migration.h" 20 #include "trace.h" 21 #include "multifd.h" 22 23 struct zstd_data { 24 /* stream for compression */ 25 ZSTD_CStream *zcs; 26 /* stream for decompression */ 27 ZSTD_DStream *zds; 28 /* buffers */ 29 ZSTD_inBuffer in; 30 ZSTD_outBuffer out; 31 /* compressed buffer */ 32 uint8_t *zbuff; 33 /* size of compressed buffer */ 34 uint32_t zbuff_len; 35 }; 36 37 /* Multifd zstd compression */ 38 39 /** 40 * zstd_send_setup: setup send side 41 * 42 * Setup each channel with zstd compression. 43 * 44 * Returns 0 for success or -1 for error 45 * 46 * @p: Params for the channel that we are using 47 * @errp: pointer to an error 48 */ 49 static int zstd_send_setup(MultiFDSendParams *p, Error **errp) 50 { 51 struct zstd_data *z = g_new0(struct zstd_data, 1); 52 int res; 53 54 p->data = z; 55 z->zcs = ZSTD_createCStream(); 56 if (!z->zcs) { 57 g_free(z); 58 error_setg(errp, "multifd %u: zstd createCStream failed", p->id); 59 return -1; 60 } 61 62 res = ZSTD_initCStream(z->zcs, migrate_multifd_zstd_level()); 63 if (ZSTD_isError(res)) { 64 ZSTD_freeCStream(z->zcs); 65 g_free(z); 66 error_setg(errp, "multifd %u: initCStream failed with error %s", 67 p->id, ZSTD_getErrorName(res)); 68 return -1; 69 } 70 /* This is the maxium size of the compressed buffer */ 71 z->zbuff_len = ZSTD_compressBound(MULTIFD_PACKET_SIZE); 72 z->zbuff = g_try_malloc(z->zbuff_len); 73 if (!z->zbuff) { 74 ZSTD_freeCStream(z->zcs); 75 g_free(z); 76 error_setg(errp, "multifd %u: out of memory for zbuff", p->id); 77 return -1; 78 } 79 return 0; 80 } 81 82 /** 83 * zstd_send_cleanup: cleanup send side 84 * 85 * Close the channel and return memory. 86 * 87 * @p: Params for the channel that we are using 88 * @errp: pointer to an error 89 */ 90 static void zstd_send_cleanup(MultiFDSendParams *p, Error **errp) 91 { 92 struct zstd_data *z = p->data; 93 94 ZSTD_freeCStream(z->zcs); 95 z->zcs = NULL; 96 g_free(z->zbuff); 97 z->zbuff = NULL; 98 g_free(p->data); 99 p->data = NULL; 100 } 101 102 /** 103 * zstd_send_prepare: prepare date to be able to send 104 * 105 * Create a compressed buffer with all the pages that we are going to 106 * send. 107 * 108 * Returns 0 for success or -1 for error 109 * 110 * @p: Params for the channel that we are using 111 * @errp: pointer to an error 112 */ 113 static int zstd_send_prepare(MultiFDSendParams *p, Error **errp) 114 { 115 struct zstd_data *z = p->data; 116 size_t page_size = qemu_target_page_size(); 117 int ret; 118 uint32_t i; 119 120 z->out.dst = z->zbuff; 121 z->out.size = z->zbuff_len; 122 z->out.pos = 0; 123 124 for (i = 0; i < p->normal_num; i++) { 125 ZSTD_EndDirective flush = ZSTD_e_continue; 126 127 if (i == p->normal_num - 1) { 128 flush = ZSTD_e_flush; 129 } 130 z->in.src = p->pages->block->host + p->normal[i]; 131 z->in.size = page_size; 132 z->in.pos = 0; 133 134 /* 135 * Welcome to compressStream2 semantics 136 * 137 * We need to loop while: 138 * - return is > 0 139 * - there is input available 140 * - there is output space free 141 */ 142 do { 143 ret = ZSTD_compressStream2(z->zcs, &z->out, &z->in, flush); 144 } while (ret > 0 && (z->in.size - z->in.pos > 0) 145 && (z->out.size - z->out.pos > 0)); 146 if (ret > 0 && (z->in.size - z->in.pos > 0)) { 147 error_setg(errp, "multifd %u: compressStream buffer too small", 148 p->id); 149 return -1; 150 } 151 if (ZSTD_isError(ret)) { 152 error_setg(errp, "multifd %u: compressStream error %s", 153 p->id, ZSTD_getErrorName(ret)); 154 return -1; 155 } 156 } 157 p->iov[p->iovs_num].iov_base = z->zbuff; 158 p->iov[p->iovs_num].iov_len = z->out.pos; 159 p->iovs_num++; 160 p->next_packet_size = z->out.pos; 161 p->flags |= MULTIFD_FLAG_ZSTD; 162 163 return 0; 164 } 165 166 /** 167 * zstd_recv_setup: setup receive side 168 * 169 * Create the compressed channel and buffer. 170 * 171 * Returns 0 for success or -1 for error 172 * 173 * @p: Params for the channel that we are using 174 * @errp: pointer to an error 175 */ 176 static int zstd_recv_setup(MultiFDRecvParams *p, Error **errp) 177 { 178 struct zstd_data *z = g_new0(struct zstd_data, 1); 179 int ret; 180 181 p->data = z; 182 z->zds = ZSTD_createDStream(); 183 if (!z->zds) { 184 g_free(z); 185 error_setg(errp, "multifd %u: zstd createDStream failed", p->id); 186 return -1; 187 } 188 189 ret = ZSTD_initDStream(z->zds); 190 if (ZSTD_isError(ret)) { 191 ZSTD_freeDStream(z->zds); 192 g_free(z); 193 error_setg(errp, "multifd %u: initDStream failed with error %s", 194 p->id, ZSTD_getErrorName(ret)); 195 return -1; 196 } 197 198 /* To be safe, we reserve twice the size of the packet */ 199 z->zbuff_len = MULTIFD_PACKET_SIZE * 2; 200 z->zbuff = g_try_malloc(z->zbuff_len); 201 if (!z->zbuff) { 202 ZSTD_freeDStream(z->zds); 203 g_free(z); 204 error_setg(errp, "multifd %u: out of memory for zbuff", p->id); 205 return -1; 206 } 207 return 0; 208 } 209 210 /** 211 * zstd_recv_cleanup: setup receive side 212 * 213 * For no compression this function does nothing. 214 * 215 * @p: Params for the channel that we are using 216 */ 217 static void zstd_recv_cleanup(MultiFDRecvParams *p) 218 { 219 struct zstd_data *z = p->data; 220 221 ZSTD_freeDStream(z->zds); 222 z->zds = NULL; 223 g_free(z->zbuff); 224 z->zbuff = NULL; 225 g_free(p->data); 226 p->data = NULL; 227 } 228 229 /** 230 * zstd_recv_pages: read the data from the channel into actual pages 231 * 232 * Read the compressed buffer, and uncompress it into the actual 233 * pages. 234 * 235 * Returns 0 for success or -1 for error 236 * 237 * @p: Params for the channel that we are using 238 * @errp: pointer to an error 239 */ 240 static int zstd_recv_pages(MultiFDRecvParams *p, Error **errp) 241 { 242 uint32_t in_size = p->next_packet_size; 243 uint32_t out_size = 0; 244 size_t page_size = qemu_target_page_size(); 245 uint32_t expected_size = p->normal_num * page_size; 246 uint32_t flags = p->flags & MULTIFD_FLAG_COMPRESSION_MASK; 247 struct zstd_data *z = p->data; 248 int ret; 249 int i; 250 251 if (flags != MULTIFD_FLAG_ZSTD) { 252 error_setg(errp, "multifd %u: flags received %x flags expected %x", 253 p->id, flags, MULTIFD_FLAG_ZSTD); 254 return -1; 255 } 256 ret = qio_channel_read_all(p->c, (void *)z->zbuff, in_size, errp); 257 258 if (ret != 0) { 259 return ret; 260 } 261 262 z->in.src = z->zbuff; 263 z->in.size = in_size; 264 z->in.pos = 0; 265 266 for (i = 0; i < p->normal_num; i++) { 267 z->out.dst = p->host + p->normal[i]; 268 z->out.size = page_size; 269 z->out.pos = 0; 270 271 /* 272 * Welcome to decompressStream semantics 273 * 274 * We need to loop while: 275 * - return is > 0 276 * - there is input available 277 * - we haven't put out a full page 278 */ 279 do { 280 ret = ZSTD_decompressStream(z->zds, &z->out, &z->in); 281 } while (ret > 0 && (z->in.size - z->in.pos > 0) 282 && (z->out.pos < page_size)); 283 if (ret > 0 && (z->out.pos < page_size)) { 284 error_setg(errp, "multifd %u: decompressStream buffer too small", 285 p->id); 286 return -1; 287 } 288 if (ZSTD_isError(ret)) { 289 error_setg(errp, "multifd %u: decompressStream returned %s", 290 p->id, ZSTD_getErrorName(ret)); 291 return ret; 292 } 293 out_size += z->out.pos; 294 } 295 if (out_size != expected_size) { 296 error_setg(errp, "multifd %u: packet size received %u size expected %u", 297 p->id, out_size, expected_size); 298 return -1; 299 } 300 return 0; 301 } 302 303 static MultiFDMethods multifd_zstd_ops = { 304 .send_setup = zstd_send_setup, 305 .send_cleanup = zstd_send_cleanup, 306 .send_prepare = zstd_send_prepare, 307 .recv_setup = zstd_recv_setup, 308 .recv_cleanup = zstd_recv_cleanup, 309 .recv_pages = zstd_recv_pages 310 }; 311 312 static void multifd_zstd_register(void) 313 { 314 multifd_register_ops(MULTIFD_COMPRESSION_ZSTD, &multifd_zstd_ops); 315 } 316 317 migration_init(multifd_zstd_register);